threadpool is a cross-platform C++ thread pool library. It provides a convenient way for dispatching asynchronous tasks and can be easily customized. threadpool is based on the high-quality Boost source libraries.

ProjectForge is a Web-based solution for project management including time sheet booking, team calendar, financial administration, and controlling and managing work-break-down-structures. A ready-to-run server and a war file are available.

pyOBD-II (a.k.a. "pyobd2") is a Python library for communicating with OBD-II vehicles. Its goal is to make writing programs for vehicle diagnostics and monitoring vehicle data as easy as possible. Relies on pySerial to communicate with ELM scanners.

As of now, you can get Ehcache only from ehcache.org or Maven central.
A simple, fast, thread safe, standards based cache for Java, and provides memory and disk stores and distributed operation for clusters. ehcache is widely used in such open source projects as Hibernate and Spring. Terracotta offers enterprise edition

Stars! Nova is a clone of the classic 4X space strategy game Stars!. While nowhere near the functionality of Stars! quite a few features have been implemented so far. See the Nova web page for details.

(XSLT transformer/editor)
A text editor that allows the loading and editing of an XML document and an XSLT document at the same time. It also can apply the XSLT to the XML and display the output for further editing/saving. Plugable XML and XSLT parsers

PizzaFactory is a distribution package for embedded software development based on Eclipse. The fullset of PizzaFactory is a commercial product. Here is a OSS version (subset but enough useful for hobby users.)

SyncML C Reference Toolkit. The purpose of this toolkit is to provide a reference implementation of the SyncML protocols. The toolkit is designed for both Clients and Servers, for a variety of platforms. More info at www.syncml.org.